By Aaruni Arora
A certain species of rodents with pink, wrinkled, hairless skin and buck teeth can be somewhat idealised as the supermodels of all animal models. Heterocephalus glaber, more commonly known as the Naked Mole Rat, is of interest to humans because of their very strange qualities. To begin with, these native East African rats have a lifespan of thirty years, are resistant to some pain stimuli, do not age, and are xenophobic. They build colonies of about three hundred rats with the Queen as their leader, the soldiers who protect the community, and the workers who dig and hunt for food. The Queen also chooses two or three males with whom she reproduces to grow the community. The rats communicate through vocalisation and each colony has a different dialect depending on their Queen. (Buffenstein, 2021)
Nonetheless, H.glaber also have some astonishing physiological capabilities as well. They are able to survive long periods with low or no oxygen. A study published by Science (Park et al., 2021) revealed that these hypoxic rodents lived up to 18 minutes with no oxygen and six hours with low amounts of oxygen. The scientists believe that this is possible because the rodents have a special type of haemoglobin, which has a higher affinity for oxygen than human haemoglobin does. Further, the rats go into a state of suspended animation (where they metabolise fructose instead of glucose) and abandon thermoregulation to reduce the usage of energy. These adaptation result in H.glaber being the only cold-blooded or heterothermic mammals who can survive on energy released through fructose decomposition.
The researcher, Gary Lewin, a neurobiologist at the Max Delbrück Center for Molecular Medicine in Berlin, said “This seems to be sort of a rescue mechanism for the mole rat’s heart and neural cells, because they can continue to use fructose even though the products of this metalysis would wind up toxic to them. But it’s more important to produce energy right away and have that risk as opposed to die and stop producing energy anyway.” (Naked mole rats can survive for 18 minutes without oxygen. Here’s why., 2021). These findings are important because when humans have a stroke or go into cardiac arrest, this mechanism can help prevent brain damage or other fatal conditions. However, there have been similar studies on other animals like woodchucks, and we still do not know how to replicate these adaptations in human beings.
The second interesting trait is the Naked Mole Rat’s resistance to cancerous cells. Before, it was believed that their immunity to oncogenesis is due to the presence of hyaluronan. When compared to the human version of this chemical, the one present in H.glaber is five times longer. Moreover, these rats have a three-part ribosome instead of two, which, according to one hypothesis, might make their ability to translate DNA and manufacture proteins more accurate.
However, a recent study by University of Cambridge (Hadi et al., 2021) showed that these rodents might not be cancer resistant after all. When a cancer-causing gene from another rat species is introduced into naked mole rats, they could still develop tumours. Thus, it is still a mystery as to what helps this particular species from developing cancer. In the same study, the findings suggested that the unique interaction between the H.glaber and their microenvironment had helped stop the initial stage of cancer from developing into tumours.
Nonetheless, there are still a lot of mysteries that are yet to be discovered and understood about naked mole rats. As Dr Ewan St. John Smith, University of Cambridge’s Department of Pharmacology, said “All our work with naked mole-rats, from studying their hypoxia resistance to pain insensitivity and cancer resistance, is aiming to leverage the extreme biology of this species to understand more about how our bodies work normally.” (Buffenstein, 2021).
References:
Buffenstein, R., 2021. Colony-specific dialects of naked mole-rats. Science, 371(6528), pp.461-462.
Park, T., Reznick, J., Peterson, B., Blass, G., Omerbašić, D., Bennett, N., Kuich, P., Zasada, C., Browe, B., Hamann, W., Applegate, D., Radke, M., Kosten, T., Lutermann, H., Gavaghan, V., Eigenbrod, O., Bégay, V., Amoroso, V., Govind, V., Minshall, R., Smith, E., Larson, J., Gotthardt, M., Kempa, S. and Lewin, G., 2021. Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat.
PBS NewsHour. 2021. Naked mole rats can survive for 18 minutes without oxygen. Here’s why.. [online] Available at: https://www.pbs.org/newshour/science/naked-mole-rats-can-survive-18-minutes-without-oxygen-heres#:~:text=Naked%20mole%20rats%20can%20survive%20for%20six%20hours%20in%20extremely,type%20of%20sugar%20%E2%80%94%20for%20fuel
Hadi, F., Kulaberoglu, Y., Lazarus, K., Bach, K., Ugur, R., Beattie, P., Smith, E. and Khaled, W., 2021. Transformation of naked mole-rat cells.
University of Cambridge. 2021. Secrets of naked mole-rat cancer resistance unearthed. [online] Available at: https://www.cam.ac.uk/research/news/secrets-of-naked-mole-rat-cancer-resistance-unearthed
Imperial Bioscience Review 